Flexible printed circuit and manufacturing method thereof, electronic device module and electronic device

ABSTRACT

A flexible printed circuit and a manufacturing method thereof, an electronic device module and an electronic device are provided. The flexible printed circuit includes a main sub-circuit board and a bridge sub-circuit board; the main sub-circuit board includes a first substrate, and a first bridge end, a second bridge end, a first wiring portion, and a second wiring portion on the first substrate, the first wiring portion and the second wiring portion are spaced apart from each other and are electrically connected to the first bridge end and the second bridge end, respectively; the bridge sub-circuit board includes a second substrate, and a third bridge end, a fourth bridge end, and a third wiring portion for a first functional wiring line on the second substrate, the third bridge end and the fourth bridge end are electrically connected by the third wiring portion, the first substrate and the second substrate are not in direct contact, and the bridge sub-circuit board is configured to be mounted on the main sub-circuit board by electrically connecting the third bridge end and the fourth bridge end to the first bridge end and the second bridge end, respectively. The wiring layout of the flexible printed circuit is simple and is easy to be manufactured.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of and Applicant claims priorityunder 35 U.S.C. § 120 of 17/864,731 filed on Jul. 14, 2022 which is adivisional of and Applicant claims priority under 35 U.S.C. §§ 120 and121 of U.S. application Ser. No. 16/958,937 filed on Jun. 29, 2020 nowU.S. Pat. No. 11,419,212 issued Aug. 16, 2022 which application is theNational Stage of PCT/CN2020/073940 filed on Jan. 23, 2020, which claimspriority under 35 U.S.C. § 119 of Chinese Application Nos.201910093341.0 filed on Jan. 30, 2019 and Chinese Application No.202010075431.X filed on Jan. 22, 2020, the disclosures of which isincorporated by reference. Certified copies of the priority ChinesePatent Application Nos. 201910093341.0 and 202010075431.X are containedin parent U.S. application Ser. No. 16/958,937.

TECHNICAL FIELD

Embodiments of the present disclosure relate to a flexible printedcircuit and a manufacturing method thereof, an electronic device moduleand an electronic device.

BACKGROUND

A flexible printed circuit (FPC) is a kind of printed circuit board withhigh reliability and flexibility, and is made of a flexible film as abase material. The flexible printed circuit has the characteristics ofhigh wiring density, light weight, thin thickness, good bendability,etc., and is widely used in various electronic devices such as mobilephones, computers, and monitors.

SUMMARY

At least one embodiment of the present disclosure provides a flexibleprinted circuit, and the flexible printed circuit comprises: a mainsub-circuit board, comprising a first substrate, and a first bridge end,a second bridge end, a first wiring portion, and a second wiring portionon the first substrate, the first wiring portion and the second wiringportion being spaced apart from each other and being electricallyconnected to the first bridge end and the second bridge end,respectively; and a bridge sub-circuit board, comprising a secondsubstrate, and a third bridge end, a fourth bridge end, and a thirdwiring portion for a first functional wiring line on the secondsubstrate, the third bridge end and the fourth bridge end beingelectrically connected by the third wiring portion; in which the firstsubstrate and the second substrate are not in direct contact, and thebridge sub-circuit board is configured to be mounted on the mainsub-circuit board by electrically connecting the third bridge end andthe fourth bridge end to the first bridge end and the second bridge end,respectively.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit board ismounted on the main sub-circuit board, and the first wiring portion, thethird wiring portion, and the second wiring portion are electricallyconnected in sequence to obtain the first functional wiring line.

For example, the flexible printed circuit provided by at least oneembodiment of the present disclosure further comprises a first controlcircuit combination structure, the first control circuit combinationstructure is on the main sub-circuit board and is electrically connectedto the first wiring portion, or the first control circuit combinationstructure is on the bridge sub-circuit board and is electricallyconnected to the third wiring portion; the first control circuitcombination structure is configured to provide a first electrical signalto the first functional wiring line or receive a first electrical signalfrom the first functional wiring line.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the main sub-circuit board furthercomprises a second functional wiring line, the second functional wiringline is electrically connected to the first control circuit combinationstructure on the main sub-circuit board, and the first control circuitcombination structure is further configured to provide a secondelectrical signal to the second functional wiring line or receive asecond electrical signal from the second functional wiring line.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the main sub-circuit board furthercomprises a third functional wiring line, and the third functionalwiring line is between the first wiring portion and the second wiringportion, and crosses the bridge sub-circuit board mounted on the mainsub-circuit board.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the first wiring portion, thesecond wiring portion, and the third functional wiring line are routedin a same direction.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the main sub-circuit boardcomprises a first main wiring layer on a first side of the firstsubstrate and a first main insulation layer stacked on a side of thefirst main wiring layer away from the first substrate, the first mainwiring layer comprises the first wiring portion, the second wiringportion, the first bridge end, and the second bridge end, and the firstbridge end and the second bridge end are exposed by the first maininsulation layer.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the main sub-circuit board furthercomprises a second main wiring layer, on a second side of the firstsubstrate opposite to the first side, and a second main insulation layerstacked on a side of the second main wiring layer away from the firstsubstrate, the second main wiring layer comprises the first wiringportion and the second wiring portion.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the main sub-circuit boardcomprises a first main wiring layer on a first side of the firstsubstrate and a first main insulation layer stacked on a side of thefirst main wiring layer away from the first substrate, the mainsub-circuit board further comprises a second main wiring layer, on asecond side of the first substrate opposite to the first side, and asecond main insulation layer stacked on a side of the second main wiringlayer away from the first substrate, the first main wiring layercomprises the first wiring portion, the second wiring portion, and thefirst bridge end, the first bridge end is exposed by the first maininsulation layer; the second main wiring layer comprises the firstwiring portion, the second wiring portion, and the second bridge end,and the second bridge end is exposed by the second main insulationlayer.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit boardcomprises a first bridge wiring layer on a first side of the secondsubstrate and a first bridge insulation layer stacked on a side of thefirst bridge wiring layer away from the second substrate, and the firstbridge wiring layer comprises the third wiring portion.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit boardfurther comprises a grounded layer on a second side of the secondsubstrate opposite to the first side, and in a case where the bridgesub-circuit board is mounted on the main sub-circuit board, the secondside is closer to the main sub-circuit board than the first side.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit boardfurther comprises a shield layer on the second side of the secondsubstrate, and the shield layer is stacked on a side of the groundedlayer away from the second substrate.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit boardfurther comprises a second bridge wiring layer on a second side of thesecond substrate opposite to the first side, and a second bridgeinsulation layer stacked on a side of the second bridge wiring layeraway from the second substrate, the second bridge wiring layer comprisesthe third wiring portion, the third bridge end, and the fourth bridgeend, the third bridge end and the fourth bridge end are exposed by thesecond bridge insulation layer; and in a case where the bridgesub-circuit board is mounted on the main sub-circuit board, the secondside is closer to the main sub-circuit board than the first side.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit boardfurther comprises a second bridge wiring layer on a second side of thesecond substrate opposite to the first side, and a second bridgeinsulation layer stacked on a side of the second bridge wiring layeraway from the second substrate, the first bridge wiring layer furthercomprises the third bridge end, and the third bridge end is exposed bythe first bridge insulation layer; and the second bridge wiring layercomprises the third wiring portion and the fourth bridge end, and thefourth bridge end is exposed by the second bridge insulation layer.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the bridge sub-circuit boardfurther comprises a shield layer on the second side of the secondsubstrate and stacked on a side of the second bridge insulation layeraway from the second substrate.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the third bridge end and thefourth bridge end of the bridging sub-circuit board are respectivelyconnected to the first bridge end and the second bridge end of the mainsub-circuit board through an anisotropic conductive adhesive, a soldermaterial, or a connector.

For example, in the flexible printed circuit provided by at least oneembodiment of the present disclosure, the main sub-circuit boardcomprises a plurality of first bridge ends and a plurality of secondbridge ends; the flexible printed circuit comprises a plurality ofbridge sub-circuit boards, and the plurality of bridge sub-circuitboards are mounted on the main sub-circuit board by electricallyconnecting a plurality of third bridge ends and a plurality of fourthbridge ends to the plurality of first bridge ends and the plurality ofsecond bridge ends, respectively.

At least one embodiment of the present disclosure provides a flexibleprinted circuit, and the flexible printed circuit comprises: a mainsub-circuit board, comprising a first substrate, and a first bridge end,a second bridge end, a first wiring portion, and a second wiring portionon the first substrate, the first wiring portion and the second wiringportion being spaced apart from each other and being electricallyconnected to the first bridge end and the second bridge end,respectively; and a bridge sub-circuit board, comprising a secondsubstrate, and a third bridge end, a fourth bridge end, and a thirdwiring portion for a first functional wiring line on the secondsubstrate, the third bridge end and the fourth bridge end beingelectrically connected by the third wiring portion. The first substrateand the second substrate are not in direct contact, and the bridgesub-circuit board is configured to be mounted on the main sub-circuitboard by electrically connecting the third bridge end and the fourthbridge end to the first bridge end and the second bridge end,respectively. The main sub-circuit board comprises a first main wiringlayer on a first side of the first substrate and a first main insulationlayer stacked on a side of the first main wiring layer away from thefirst substrate, the first main wiring layer comprises the first wiringportion, the second wiring portion, the first bridge end, and the secondbridge end, and the first bridge end and the second bridge end areexposed by the first main insulation layer; the main sub-circuit boardfurther comprises a second main wiring layer, on a second side of thefirst substrate opposite to the first side, and a second main insulationlayer stacked on a side of the second main wiring layer away from thefirst substrate, the second main wiring layer comprises the first wiringportion and the second wiring portion; the bridge sub-circuit boardcomprises a first bridge wiring layer on a first side of the secondsubstrate and a first bridge insulation layer stacked on a side of thefirst bridge wiring layer away from the second substrate, and the firstbridge wiring layer comprises the third wiring portion; the bridgesub-circuit board further comprises a second bridge wiring layer on asecond side of the second substrate opposite to the first side, and asecond bridge insulation layer stacked on a side of the second bridgewiring layer away from the second substrate, the second bridge wiringlayer comprises the third wiring portion, the third bridge end, and thefourth bridge end, the third bridge end and the fourth bridge end areexposed by the second bridge insulation layer. In a case where thebridge sub-circuit board is mounted on the main sub-circuit board, thesecond side is closer to the main sub-circuit board than the first side.

At least one embodiment of the present disclosure provides an electronicdevice module, and the electronic device module comprises an electronicdevice substrate and the flexible printed circuit according to any oneof the above embodiments; the electronic device substrate comprises afirst functional circuit structure, and the first functional wiring lineof the flexible printed circuit is electrically connected to the firstfunctional circuit structure.

For example, in the electronic device module provided by at least oneembodiment of the present disclosure, the flexible printed circuitfurther comprises a second functional wiring line, the first functionalcircuit structure comprises a first signal transmission portion and asecond signal transmission portion, the first functional wiring line iselectrically connected to the first signal transmission portion, and thesecond functional wiring line is electrically connected to the secondsignal transmission portion.

For example, in the electronic device module provided by at least oneembodiment of the present disclosure, the electronic device substratefurther comprises a second functional circuit structure, and theflexible printed circuit further comprises a third functional wiringline, and the third functional wiring line is electrically connected tothe second functional circuit structure.

For example, in the electronic device module provided by at least oneembodiment of the present disclosure, the first functional circuitstructure is a touch circuit structure, and the second functionalcircuit structure is a display circuit structure.

For example, in the electronic device module provided by at least oneembodiment of the present disclosure, the first signal transmissionportion is a touch driving circuit of the touch circuit structure, andthe second signal transmission portion is a touch sensing circuit of thetouch circuit structure; or the first signal transmission portion is atouch sensing circuit of the touch circuit structure, and the secondsignal transmission portion is a touch driving circuit of the touchcircuit structure.

At least one embodiment of the present disclosure provides an electronicdevice, which comprises the electronic device module according to anyone of the above embodiments.

At least one embodiment of the present disclosure provides amanufacturing method fora flexible printed circuit, which comprises:providing a main sub-circuit board, the main sub-circuit boardcomprising a first substrate, and a first bridge end, a second bridgeend, a first wiring portion, and a second wiring portion on the firstsubstrate, the first wiring portion and the second wiring portion beingspaced apart from each other and are electrically connected to the firstbridge end and the second bridge end, respectively; providing a bridgesub-circuit board, the bridge sub-circuit board comprising a secondsubstrate, and a third bridge end, a fourth bridge end, and a thirdwiring portion for a first functional wiring line on the secondsubstrate, the third bridge end and the fourth bridge end beingelectrically connected by the third wiring portion; and electricallyconnecting the third bridge end and the fourth bridge end of the bridgesub-circuit board to the first bridge end and the second bridge end ofthe main sub-circuit board, respectively, so that the bridge sub-circuitboard is mounted on the main sub-circuit board, and the first substrateand the second substrate are not in direct contact.

For example, in the manufacturing method for a flexible printed circuitprovided by at least one embodiment of the present disclosure, the thirdbridge end and the fourth bridge end of the bridge sub-circuit board arerespectively connected to the first bridge end and the second bridge endof the main sub-circuit board through a hot pressing method, a weldingmethod, or through a connector.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to clearly illustrate the technical solutions of theembodiments of the disclosure, the drawings of the embodiments will bebriefly described in the following; it is obvious that the describeddrawings are only related to some embodiments of the disclosure and thusare not limitative to the disclosure.

FIG. 1A is a schematic plan diagram of a flexible printed circuitprovided by at least one embodiment of the present disclosure;

FIG. 1B is a schematic plan diagram of a flexible printed circuitprovided by at least one embodiment of the present disclosure;

FIG. 1C is a schematic plan diagram of a flexible printed circuitprovided by at least one embodiment of the present disclosure;

FIG. 1D is a schematic plan diagram of a flexible printed circuitprovided by at least one embodiment of the present disclosure;

FIG. 2 is a schematic plan diagram of a main sub-circuit board of aflexible printed circuit provided by at least one embodiment of thepresent disclosure;

FIG. 3 is a schematic plan diagram of a bridge sub-circuit board of aflexible printed circuit provided by at least one embodiment of thepresent disclosure;

FIG. 4A is a schematic plan diagram of a main sub-circuit board of aflexible printed circuit provided by at least one embodiment of thepresent disclosure;

FIG. 4B is a schematic plan diagram of a bridge sub-circuit board of aflexible circuit board provided by at least one embodiment of thepresent disclosure:

FIG. 5A is a schematic plan diagram of a main sub-circuit board of aflexible printed circuit provided by at least one embodiment of thepresent disclosure;

FIG. 5B is a schematic plan diagram of a main sub-circuit board of aflexible printed circuit provided by at least one embodiment of thepresent disclosure;

FIG. 6A is a schematic cross-sectional diagram of a main sub-circuitboard of a flexible printed circuit provided by at least one embodimentof the present disclosure;

FIG. 6B is a schematic cross-sectional diagram of a main sub-circuitboard of a flexible printed circuit provided by at least one embodimentof the present disclosure;

FIG. 7A is another schematic cross-sectional diagram of a mainsub-circuit board of a flexible printed circuit provided by at least oneembodiment of the present disclosure;

FIG. 7B is another schematic cross-sectional diagram of a mainsub-circuit board of a flexible printed circuit provided by at least oneembodiment of the present disclosure;

FIG. 8A is a schematic cross-sectional diagram of a bridge sub-circuitboard of a flexible printed circuit provided by at least one embodimentof the present disclosure;

FIG. 8B is a schematic cross-sectional diagram of a bridge sub-circuitboard of a flexible printed circuit provided by at least one embodimentof the present disclosure;

FIG. 8C is a schematic cross-sectional diagram of a bridge sub-circuitboard of a flexible printed circuit provided by at least one embodimentof the present disclosure;

FIG. 8D is a schematic cross-sectional diagram of a bridge sub-circuitboard of a flexible printed circuit provided by at least one embodimentof the present disclosure;

FIG. 9A is another schematic cross-sectional diagram of a bridgesub-circuit board of a flexible printed circuit provided by at least oneembodiment of the present disclosure;

FIG. 9B is another schematic cross-sectional diagram of a bridgesub-circuit board of a flexible printed circuit provided by at least oneembodiment of the present disclosure;

FIG. 10A is a schematic diagram of an electronic device module providedby at least one embodiment of the present disclosure:

FIG. 10B is a schematic diagram of another electronic device moduleprovided by at least one embodiment of the present disclosure;

FIG. 11 is a schematic diagram of an electronic device provided by someembodiments of the present disclosure; and

FIG. 12 is a flowchart of manufacturing a flexible printed circuitprovided by some embodiments of the present disclosure.

DETAILED DESCRIPTION

In order to make objects, technical details and advantages of theembodiments of the disclosure apparent, the technical solutions of theembodiments will be described in a clearly and fully understandable wayin connection with the drawings related to the embodiments of thedisclosure. Apparently, the described embodiments are just a part butnot all of the embodiments of the disclosure. Based on the describedembodiments herein, those skilled in the art can obtain otherembodiment(s), without any inventive work, which should be within thescope of the disclosure.

Unless otherwise defined, all the technical and scientific terms usedherein have the same meanings as commonly understood by one of ordinaryskill in the art to which the present disclosure belongs. The terms“first,” “second,” etc., which are used in the present disclosure, arenot intended to indicate any sequence, amount or importance, butdistinguish various components. The terms “comprise,” “comprising,”“include,” “including,” etc., are intended to specify that the elementsor the objects stated before these terms encompass the elements or theobjects and equivalents thereof listed after these terms, but do notpreclude the other elements or objects. The phrases “connect”,“connected”, etc., are not intended to define a physical connection ormechanical connection, but may include an electrical connection,directly or indirectly. “On,” “under,” “right,” “left” and the like areonly used to indicate relative position relationship, and when theposition of the object which is described is changed, the relativeposition relationship may be changed accordingly.

A variety of signal wiring lines can usually be integrated on a flexibleprinted circuit and are used to transmit different types of signals. Ina case where there are many types of signal wiring lines on the flexibleprinted circuit, for example, in a case where a plurality of signalwiring lines for display signals, touch signals, fingerprintidentification signals, etc. are required at the same time, the wiringdifficulty in the flexible printed circuit will also increase. In thisregard, the flexible printed circuit is often formed with a plurality oflayers of wiring lines, for example, with four or six layers of wiringlines, etc., so as to facilitate the arrangement of various wiringlines, so that the plurality of wiring lines can be distributed ondifferent layers, thereby reducing the mutual interference betweendifferent types of wiring lines. However, in the process ofmanufacturing a flexible printed circuit with a plurality of wiringlayers, it is also necessary to form an insulation layer (and acorresponding adhesive layer) between adjacent wiring layers, ifnecessary, in order to avoid signal crosstalk between different wiringlines, it is also necessary to form a (electromagnetic signal) shieldlayer between different wiring lines, which further increases thedifficulty of manufacturing the flexible printed circuit.

At least one embodiment of the present disclosure provides a flexibleprinted circuit, and the flexible printed circuit includes a mainsub-circuit board and a bridge sub-circuit board, the main sub-circuitboard includes a first substrate, and a first bridge end, a secondbridge end, a first wiring portion, and a second wiring portion providedon the first substrate; the first wiring portion and the second wiringportion are spaced apart from each other and are electrically connectedto the first bridge end and the second bridge end, respectively; thebridge sub-circuit board includes a second substrate, and a third bridgeend, a fourth bridge end, and a third wiring portion provided on thesecond substrate, the third bridge end and the fourth bridge end areelectrically connected by the third wiring portion, the first substrateand the second substrate are not in direct contact, and the bridgesub-circuit board is configured to be mounted on the main sub-circuitboard by electrically connecting the third bridge end and the fourthbridge end to the first bridge end and the second bridge end,respectively.

At least one embodiment of the present disclosure provides an electronicdevice module, which includes an electronic device substrate and theabove flexible printed circuit; the electronic device substrate includesa first functional circuit structure, and the first functional wiringline of the flexible printed circuit is electrically connected to thefirst functional circuit structure.

At least one embodiment of the present disclosure provides an electronicdevice, which includes the above electronic device module.

The flexible printed circuit and a manufacturing method thereof, anelectronic device module, and an electronic device provided by thepresent disclosure will be described below through several specificembodiments.

Some embodiments of the present disclosure provide a flexible printedcircuit, and FIG. 1A is a schematic plan diagram of the flexible printedcircuit. As shown in FIG. 1A, the flexible printed circuit 10 includes amain sub-circuit board 100 and a bridge sub-circuit board 200, and thebridge sub-circuit board 200 can be electrically connected to the mainsub-circuit board 100.

FIG. 2 is a schematic plan diagram of the main sub-circuit board 100. Asshown in FIG. 2 , the main sub-circuit board 100 includes a firstsubstrate, and a first bridge end 101, a second bridge end 102, a firstwiring portion 103, and a second wiring portion 104 provided on thefirst substrate; the first wiring portion 103 and the second wiringportion 104 are spaced apart from each other by a predetermined space(distance), and are electrically connected to the first bridge end 101and the second bridge end 102, respectively. For example, the firstbridge end 101 includes a plurality of first contact pads, and thesecond bridge end 102 includes a plurality of second contact pads. Forexample, the first wiring portion 103 includes a plurality of wiringlines, and ends of the plurality of wiring lines included in the firstwiring portion 103 are electrically connected to the plurality of firstcontact pads included in the first bridge end 101 in one-to-onecorrespondence; the second wiring portion 104 also includes a pluralityof wiring lines, and ends of the plurality of wiring lines included inthe second wiring portion 104 are electrically connected to theplurality of second contact pads included in the second bridge end 102in one-to-one correspondence. Although only two wiring lines included inthe first wiring portion 103 and two wiring lines included in the secondwiring portion 104 are shown in the figure, the embodiments of thepresent disclosure are not limited thereto.

FIG. 3 is a schematic plan diagram of the bridge sub-circuit board 200.As shown in FIG. 3 , the bridge sub-circuit board 200 includes a secondsubstrate, and a third bridge end 201, a fourth bridge end 202, and athird wiring portion 203 provided on the second substrate, the thirdbridge end 201 and the fourth bridge end 202 are electrically connectedby the third wiring portion 203. For example, the third bridge end 201includes a plurality of third contact pads, the fourth bridge end 202includes a plurality of fourth contact pads, and the third wiringportion 203 includes a plurality of wiring lines, and these wiring linesare electrically connected in one-to-one correspondence with theplurality of third contact pads included in the third bridge end 201 atone ends, and are electrically connected in one-to-one correspondencewith the plurality of fourth contact pads included in the fourth bridgeend 202 at the other ends. Although only two wiring lines included inthe third wiring portion 203 are shown in the figure, the embodiments ofthe present disclosure are not limited thereto.

The bridge sub-circuit board 200 is configured to be able to be mountedon the main sub-circuit board 100 by electrically connecting the thirdbridge end 201 and the fourth bridge end 202 to the first bridge end 101and the second bridge end 102, respectively. In a case where the bridgesub-circuit board 200 is mounted on the main sub-circuit board 100, thefirst wiring portion 103, the third wiring portion 203, and the secondwiring portion 104 are electrically connected in sequence to obtain thefirst functional wiring line, and therefore an electrical signal can betransmitted from the first wiring portion 103 through the third wiringportion 203 to the second wiring portion 104, or can be transmitted fromthe second wiring portion 104 through the third wiring portion 203 tothe first wiring portion 103.

For example, FIG. 1A shows a case where the bridge sub-circuit board 200is mounted on the main sub-circuit board 100 by electrically connectingthe third bridge end 201 and the fourth bridge end 202 to the firstbridge end 101 and the second bridge end 102, respectively, in someembodiments, the main sub-circuit board 100 and the bridge sub-circuitboard 200 may also be in a state to be connected, that is, the separatemain sub-circuit board 100 and the separate bridge sub-circuit board 200are also within the protection scope of the present disclosure.

For example, in some embodiments, as shown in FIG. 2 , the flexibleprinted circuit 10 may further include a first control circuitcombination structure 105, and the first control circuit combinationstructure 105 is disposed on the main sub-circuit board 100. Forexample, the first control circuit combination structure 105 includes aplurality of contact pads for mounting a first control circuit, a partof the plurality of contact pads is electrically connected to the otherends of the plurality of wiring lines included in the first wiringportion 103 in one-to-one correspondence. The first control circuitcombination structure 105 is configured to provide a first electricalsignal to the first functional wiring line or receive a first electricalsignal from the first functional wiring line.

For example, the first control circuit may be a driving IC chip. Thereare many methods (that is, package methods) to connect the driving ICchip with the flexible printed circuit, such as a tape carrier package(TCP) method, a chip on film (COF) package method, etc. In the TCPmethod, the flexible printed circuit includes a plurality of contactpads, and a plurality of pins of the driving IC chip are soldered (suchas eutectic soldering) to the plurality of contact pads of the flexibleprinted circuit in one-to-one correspondence, or are electricallyconnected to the plurality of contact pads of the flexible printedcircuit in one-to-one correspondence through an anisotropic conductiveadhesive (ACF), and the soldered portion is protected at least by, forexample, epoxy resin; in order to increase the bendability of theflexible printed circuit in the TCP method, a slit may be formed in thepackage portion. In the COF package method, the flexible printed circuitincludes a plurality of contact pads, and the plurality of pins of thedriving IC chip are directly crimped on the plurality of contact pads ofthe flexible printed circuit through the ACF, so that the plurality ofpins of the driving IC chip are electrically connected to the pluralityof contact pads of the flexible printed circuit in one-to-onecorrespondence. For example, the size, the arrangement, and the like ofthe contact pads, which are used to combine the driving IC chip, on theflexible printed circuit can be adjusted according to different types ofpackage methods or the driving IC chip to be packaged, for example,these contact pads can be arranged in a strip shape or a rectangularshape. The embodiments of the present disclosure do not limit thepackage method for the driving IC chip.

For example, in some embodiments, as shown in FIG. 2 , the mainsub-circuit board 100 of the flexible printed circuit 10 may furtherinclude a second functional wiring line 106, and the second functionalwiring line 106 includes a plurality of wiring lines. Another part ofthe contact pads in the first control circuit combination structure 105is electrically connected to the plurality of wiring lines included inthe second functional wiring line 106 in one-to-one correspondence, inthis case, the first control circuit mounted on the first controlcircuit combination structure 105 is further configured to provide asecond electrical signal to the second functional wiring line 106 orreceive a second electrical signal from the second functional wiringline 106.

For example, in some embodiments, as shown in FIGS. 1A and 2 , the mainsub-circuit board 100 of the flexible printed circuit 10 furtherincludes a third functional wiring line 107, and the third functionalwiring line 107 is located between the first wiring portion 103 and thesecond wiring portion 104, thereby passing through the predeterminedspace between the first wiring portion 103 and the second wiring portion104, for example, the third functional wiring line 107 crosses thebridge sub-circuit board 200 mounted on the main sub-circuit board 100in a direction perpendicular to a board surface of the main sub-circuitboard 100. In this case, the third wiring portion 203 on the bridgesub-circuit board 200 crosses the third functional wiring line 107 toelectrically connect the first wiring portion 103 and the second wiringportion 104 on two sides of the main sub-circuit board 100, so as toavoid forming crossed wiring lines on the main sub-circuit board 100itself, so that signal crosstalk between different wiring lines can beavoided or reduced, or additional functional layers can be avoided toprevent signal crosstalk, thereby avoiding the complexity of the circuitboard structure; in addition, the design can also simplify the wiringlayout of the main sub-circuit board 100, so that the manufacturingprocess of the main sub-circuit board becomes simple.

For example, in some embodiments, as shown in FIG. 2 , the first wiringportion 103, the second wiring portion 104, and the third functionalwiring line 107 are routed in the same direction, such as parallelrouting or substantially parallel routing (as long as the wiring linesdo not cross each other), such as the parallel routing in a verticaldirection shown in the figure. Thereby, the above-mentioned variouswiring lines on the main sub-circuit board 100 have no crossing parts,and the wiring layout is simpler. For example, in some embodiments,these wiring lines may be arranged in the same wiring layer, therebyreducing the number of wiring layers and simplifying a layered structureof the flexible printed circuit.

For example, in some embodiments, as shown in FIGS. 1B and 2 , theflexible printed circuit 10 may further include a second control circuitcombination structure 108, and the second control circuit combinationstructure 108 is disposed on the main sub-circuit board 100. Forexample, the second control circuit combination structure 108 includes aplurality of contact pads for mounting the second control circuit, andat least a part of the plurality of contact pads is electricallyconnected to one end of the third functional wiring line 107 inone-to-one correspondence. The second control circuit combinationstructure 108 is configured to provide a third electrical signal to thethird functional wiring line 107 or receive a third electrical signalfrom the third functional wiring line 107. For example, the thirdfunctional wiring line 107 is divided into two parts, a first part ofthe third functional wiring line 107 is electrically connected to afirst end (shown as a lower end in the figure) of the second controlcircuit combination structure 108, and a second part of the thirdfunctional wiring line 107 is electrically connected between a secondend (shown as an upper end in the figure) of the second control circuitcombination structure 108 and a contact pad (as described below) formedon one side edge of the main sub-circuit board 100.

For example, the second control circuit may be a driving IC chip. Thefirst control circuit and the second control circuit are used toimplement different driving functions. As described above, the method bywhich the driving IC chip is connected to the flexible printed circuitis, for example, a tape carrier package (TCP) method, a chip on film(COF) package method, and the like. For example, the second controlcircuit combination structure 108 includes a plurality of contact padsfor connecting with the driving IC chip. Similarly, the size, thearrangement, and the like of the contact pads can be adjusted accordingto different types of package methods or the driving IC chip to bepackaged. The embodiments of the present disclosure are not limited inthis aspect.

For example, as shown in FIGS. 4A and 4B, in some embodiments, the firstcontrol circuit combination structure 105 may also be formed on thebridge sub-circuit board 200, in this case, on the main sub-circuitboard 100, the first wiring portion 103 and the second wiring portion104 are electrically connected to the first bridge end 101 and thesecond bridge end 102, respectively, on the bridge sub-circuit board200, the third wiring portion 203 is divided into two parts, a firstpart of the third wiring portion 203 is electrically connected betweenthe first control circuit combination structure 105 and the third bridgeend 201, and a second part of the third wiring portion 203 iselectrically connected between the first control circuit combinationstructure 105 and the fourth bridge end 202. Thus, the first wiringportion 103 and the second wiring portion 104 on the main sub-circuitboard 100 are electrically connected to the first control circuitcombination structure 105 on the bridge sub-circuit board 200,respectively.

For example, in some embodiments, as shown in FIG. 1C, there may be aplurality of bridge sub-circuit boards 200 (shown as two in the figure).In this case, the plurality of bridge sub-circuit boards 200 may besimultaneously mounted on the main sub-circuit board 100. For example,the main sub-circuit board 100 includes a plurality of first bridge ends101 and a plurality of second bridge ends 102, and the plurality ofbridge sub-circuit boards 200 are mounted on the main sub-circuit board100 by electrically connecting a plurality of third bridge ends 201 anda plurality of fourth bridge ends 202 on the plurality of bridgesub-circuit boards 200 to the plurality of first bridge ends 101 and theplurality of second bridge ends 102, respectively.

It should be noted that, in the embodiment shown in FIG. 1C, there aretwo bridge sub-circuit boards 200, but the embodiments of the presentdisclosure are not limited to this, the number of bridge sub-circuitboards 200 can be selected according to actual needs. The embodiments ofthe present disclosure do not limit the number of bridge sub-circuitboards 200.

In addition, the embodiments of the present disclosure do notspecifically limit the method for setting the bridge sub-circuit boards200. For example, in the above embodiments, the bridge sub-circuit board200 is arranged horizontally, so as to bridge-connect the wiring lineson the left side of the main sub-circuit board 100 and the wiring lineson the right side of the main sub-circuit board 100, and the wiringlines located in a middle part of the main sub-circuit board 100 passesunder the bridge sub-circuit board 200. In other embodiments, as shownin FIG. 1D, the arrangement direction of the bridge sub-circuit board200 may also be a vertical direction, thereby bridge-connecting thewiring lines located on the upper side of the main sub-circuit board 100and the wiring lines located on the lower side of the main sub-circuitboard 100, and the wiring lines on the left side and the right side ofthe main sub-circuit board 100 pass under the bridge sub-circuit board200.

For example, FIG. 5A shows a schematic plan diagram of another mainsub-circuit board provided by an embodiment of the present disclosure.The main sub-circuit board adopts a shape and a circuit arrangement thatare different from those in the above embodiments.

For example, as shown in FIG. 5 , the main sub-circuit board is in along strip shape, and the structures, such as the first bridge end 101,the second bridge end 102, the first wiring portion 103, the secondwiring portion 104, the second functional wiring line 106, and the like,of the main sub-circuit board have the similar arrangement to thearrangement of those of the main sub-circuit board of the aboveembodiments. The main sub-circuit board in this embodiment is differentfrom the main sub-circuit board of the above embodiments in that: in themain sub-circuit board shown in FIG. 5 , the third wiring portion 107extends along the middle part of the main sub-circuit board, turns tothe left side of the main sub-circuit board on one side (the lower sideshown in the figure) of the main sub-circuit board, and is electricallyconnected to a wiring connection end 111 on the left side of the mainsub-circuit board. The wiring connection end 111 has a plurality ofcontact pads, and the plurality of wiring lines in the third wiringportion 107 are electrically connected to the plurality of contact padson the connection wiring end 11 in one-to-one correspondence. Forexample, the wiring connection end 111 may be used for electricalconnection with other electronic devices, control chips, or the like,and the embodiments of the present disclosure do not limit this.

For example, in some embodiments, the main sub-circuit board may be asingle-layer wiring structure or a multi-layer wiring structure (such asa double-layer wiring structure or a three-layer wiring structure,etc.), and the embodiments of the present disclosure do not limit this.

For example, FIG. 6A shows a schematic cross-sectional diagram of a mainsub-circuit board provided by some embodiments of the presentdisclosure. The cross-sectional diagram is obtained by taking along aline A-A in FIG. 2 , for example. In these embodiments, the mainsub-circuit board 100 has a single-layer wiring structure. As shown inFIG. 6A, the main sub-circuit board 100 includes a first substrate 1001,and a first main wiring layer 1002 and a first main insulation layer1003 stacked on one side of the first substrate 1001. The first mainwiring layer 1002 includes structures such as the first wiring portion103, the second wiring portion 104, the first bridge end 101, the secondbridge end 102, and the like. The first bridge end 101 and the secondbridge end 102 are exposed by the first main insulation layer 1003. Forexample, the first main insulation layer 1003 serves as a protectivelayer, and provides structural and electrical protection for the firstmain wiring layer 1002. For example, the first main insulation layer1003 may be bonded to the first main wiring layer 1002 and the firstsubstrate 1001 through an adhesive layer (not shown). For example, anopening 1013 is formed in the first main insulation layer 1003, and inthe opening 1013, for example, a portion of the exposed first wiringlayer 1002 corresponding to the first bridge end 101 or the secondbridge end 102 may be surface-treated (such as plated a solder layer) toform a plurality of patterned contact pads, thereby correspondinglyforming the first bridge end 101 or the second bridge end 102.

For example, in a case where the main sub-circuit board further includesthe second functional wiring line 106 and the third functional wiringline 107, the second functional wiring line 106 and the third functionalwiring line 107 are also arranged in the first main wiring layer 1002.In this case, the main sub-circuit board is a single-layer wiringstructure with a single-layer wiring layer.

For example, FIG. 6B shows a schematic cross-sectional diagram ofanother main sub-circuit board provided by some embodiments of thepresent disclosure. The cross-sectional diagram is obtained by cuttingalong the line A-A in FIG. 2 , for example. In these embodiments, themain sub-circuit board 100 has a multi-layer wiring structure, and theembodiments are described below with reference to FIG. 6B by taking themain sub-circuit board 100 having a double-layer wiring structure as anexample, but the embodiments of the present disclosure are not limitedthereto.

As shown in FIG. 6B, in this example, the main sub-circuit board 100includes a first substrate 1001, and a first main wiring layer 1002 anda first main insulation layer 1003 stacked on a first side (shown as anupper side in the figure) of the first substrate 1001, and furthercomprises a second main wiring layer 1004 and a second main insulationlayer 1005 stacked on a second side (shown as a lower side in thefigure) of the first substrate 1001. The first main insulation layer1003 serves as a protective layer, and provides structural andelectrical protection for the first main wiring layer 1002, for example,the first main insulation layer 1003 may be bonded to the first mainwiring layer 1002 and the first substrate 1001 through an adhesive layer(not shown in the figure); the second main insulation layer 1005 servesas a protective layer to provide structural and electrical protectionfor the second main wiring layer 1004. For example, the second maininsulation layer 1005 may be bonded to the second main wiring layer 1004and the first substrate 1001 through an adhesive layer (not shown in thefigure).

For example, in some examples, the first main wiring layer 1002 includesthe first wiring portion 103 and the second wiring portion 104, in thiscase, the first wiring portion 103 and the second wiring portion 104 maybe arranged alternately in the first main wiring layer 1002 and thesecond main wiring layer 1004. For example, the two adjacent wiringlines of the first wiring portion 103 along the board surface of themain sub-circuit board 100 may be located in the first main wiring layer1002 and the second main wiring layer 1004, respectively, therebyfacilitating the wiring layout. For example, the second wiring portion104 may be similarly provided.

For example, in a case where the main sub-circuit board further includesthe second functional wiring line 106 and the third functional wiringline 107, the second functional wiring line 106 and the third functionalwiring line 107 may also be arranged alternately in the first mainwiring layer 1002 and the second main wiring layer 1004. Alternatively,the first main wiring layer 1002 may include the first wiring portion103 and the second wiring portion 104, and the second main wiring layer1004 may include the second functional wiring line 106 and the thirdfunctional wiring line 107, that is, different functional wiring linesmay be arranged on different wiring layers. The embodiments of thepresent disclosure do not specifically limit the wiring layout on themain sub-circuit board 100.

For example, in the embodiment shown in FIG. 5A, in a case where thefirst wiring portion 103, the second wiring portion 104, the secondfunctional wiring line 106, and the third functional wiring line 107 onthe main sub-circuit board 100 are alternately arranged in the firstmain wiring layer 1002 and the second main wiring layer 1004, aschematic plan diagram of the first main wiring layer 1002 is shown inFIG. 5A, and a schematic plan diagram of the second main wiring layer1004 is shown in FIG. 5B. In this case, the wiring lines in the secondmain wiring layer 1004 have a similar arrangement to the wiring lines inthe first main wiring layer 1002, and the wiring lines in the secondmain wiring layer 1004 can be electrically connected to the first mainwiring layer 1002 through via holes (for example, black dots shown inFIG. 5B) and exposed by a corresponding insulation layer to form abridge end.

For example, in some embodiments, as shown in FIG. 6B, the first bridgeend 101 and the second bridge end 102 may be exposed by the first maininsulation layer 1003. For example, similarly, an opening 1013 is formedin the first main insulation layer 1003, and in the opening 1013, forexample, surface treatment can be performed on a portion of the exposedfirst main wiring layer 1002 corresponding to the first bridge end 101or the second bridge end 102, so as to form a plurality of patternedcontact pads and correspondingly form the first bridge end 101 or thesecond bridge end 102; similarly, for the wiring lines in the secondmain wiring layer 1004, the bridge end may be formed by the wiring linespassing through the via hole 1011 in the first substrate 1001, the firstmain wiring layer 1002, and the opening 1013 of the first maininsulation layer 1003. For example, the via hole 1011 in the firstsubstrate 1001 and the opening 1013 of the first main insulation layer1003 are arranged in a misaligned manner. Therefore, in themanufacturing process, the position of the opening 1013 is relativelyflat, thereby facilitating the formation of the contact pads.

For example, in some embodiments, the first bridge end 101 and thesecond bridge end 102 may be exposed on different sides of the mainsub-circuit board, respectively, so that the first bridge end 101 andthe second bridge end 102 are disposed on different sides of the mainsub-circuit board.

For example, FIG. 7A shows a schematic cross-sectional diagram of a mainsub-circuit board provided by some embodiments of the presentdisclosure. The cross-sectional diagram is obtained by cutting along aline C-C in FIG. 2 , for example. In this embodiment, the mainsub-circuit board has a single-layer wiring structure. The first bridgeend 101 of the main sub-circuit board is exposed by the first maininsulation layer 1003, as shown in FIG. 6A; and the second bridge end102 is exposed by the first substrate 1001, so that the first bridge end101 and the second bridge end 102 are disposed on different sides of themain sub-circuit board.

For example, FIG. 7B shows a schematic cross-sectional diagram ofanother main sub-circuit board provided by some embodiments of thepresent disclosure. The cross-sectional diagram is obtained by cuttingalong the line C-C in FIG. 2 , for example. In this embodiment, the mainsub-circuit board has a double-layer wiring structure. The first bridgeend 101 of the main sub-circuit board is exposed by the first maininsulation layer 1003, as shown in FIG. 6B; and the second bridge end102 is exposed by the second main insulation layer 1005, so that thefirst bridge end 101 and the second bridge end 102 are disposed ondifferent sides of the main sub-circuit board.

For example, in some embodiments, the main sub-circuit board may alsohave a multi-layer wiring structure such as a three-layer wiringstructure, a four-layer wiring structure, or the like. In this case, thevarious wiring portions on the main sub-circuit board, for example, thefirst wiring portion, the second wiring portion, the second functionalwiring line, and the third functional wiring line may be arranged in aplurality of wiring layers. For example, the first wiring portion, thesecond wiring portion, the second functional wiring line, and the thirdfunctional wiring line are alternately arranged in the plurality ofwiring layers, or are respectively arranged in different wiring layers.The embodiments of the present disclosure do not specifically limit thenumber of wiring layers of the main sub-circuit board and thearrangement of the wiring lines.

Similarly, the bridge sub-circuit board may also have a single-layerwiring structure or a multi-layer wiring structure. For example, FIG. 8Ashows a schematic cross-sectional diagram of a bridge sub-circuit boardprovided by some embodiments of the present disclosure. Thecross-sectional diagram is obtained by cutting along a line B-B in FIG.3A. In these embodiments, the bridge sub-circuit board 200 has asingle-layer wiring structure.

For example, as shown in FIG. 8A, the bridge sub-circuit board 200includes a second substrate 2001 and a first bridge wiring layer 2002and a first bridge insulation layer 2003 on a first side (shown as anupper side in the figure) of the second substrate 2001, the first bridgewiring layer 2002 includes a third wiring portion 203. Similarly, thefirst bridge insulation layer 2003 serves as a protective layer, andprovides structural and electrical protection for the first bridgewiring layer 2002. For example, the first bridge insulation layer 2003may be bonded to the first bridge wiring layer 2002 and the secondsubstrate 2001 through an adhesive layer (not shown in the figure).

For example, the second substrate 2001 has an opening 2011, in theopening 2011, for example, a portion of the exposed first bridge wiringlayer 2002 corresponding to the third bridge end 201 or the fourthbridge end 202 may be surface-treated to form a plurality of patternedcontact pads, thereby correspondingly forming the third bridge end 201or the fourth bridge end 202.

For example, in some embodiments, as shown in FIG. 8B, the bridgesub-circuit board 200 may further include a shield layer 2006, theshield layer 2006 is disposed on a side of the second substrate 2001away from the first bridge wiring layer 2002. For example, the shieldlayer 2006 can be grounded, thereby achieving the effect ofelectromagnetic shielding and preventing signal crosstalk generatedbetween the wiring lines in the main sub-circuit board and the wiringlines in the bridge sub-circuit board. For example, the shield layer2006 has a hollow structure 2016, the hollow structure 2016 correspondsto the opening 2011 in the second substrate 2001 to expose the thirdbridge end 201 or the fourth bridge end 202.

For example, FIG. 8C shows a schematic cross-sectional diagram ofanother bridge sub-circuit board provided by some embodiments of thepresent disclosure. The cross-sectional diagram is obtained by takingalong the line B-B in FIG. 3A, for example. In these embodiments, thebridge sub-circuit board 200 has a multi-layer structure. The followingembodiments describe the bridge sub-circuit board 200 having adouble-layer structure as an example with reference to FIG. 8C, but theembodiments of the present disclosure are not limited thereto.

As shown in FIG. 8C, the bridge sub-circuit board 200 includes a secondsubstrate 2001 and a first bridge wiring layer 2002 and a first bridgeinsulation layer 2003 on a first side (shown as the upper side in thefigure) of the second substrate 2001, and the first bridge wiring layer2002 includes the third wiring portion 203. Similarly, the first bridgeinsulation layer 2003 serves as a protective layer, and providesstructural and electrical protection for the first bridge wiring layer2002. For example, the first bridge insulation layer 2003 may be bondedto the first bridge wiring layer 2002 and the second substrate 2001through an adhesive layer (not shown in the figure).

For example, as shown in FIG. 8C, the bridge sub-circuit board 200 mayfurther include a second bridge wiring layer 2004 on a second side(shown as the lower side in the figure) of the second substrate 2001opposite to the first side and a second bridge insulation layer 2005stacked with the second bridge wiring layer 2004. For example, thesecond bridge wiring layer 2004 may also include the third wiringportion 203. In this case, the third wiring portion 203 may bealternately arranged in the first bridge wiring layer 2002 and thesecond bridge wiring layer 2004. For example, the two wiring lines ofthe third wiring portion 203 adjacent to each other along the boardsurface of the bridge sub-circuit board 200 may be located in the firstbridge wiring layer 2002 and the second bridge wiring layer 2004,respectively, thereby facilitating the wiring layout. For example, thedotted line in FIG. 8D indicates that the wiring portions on two sidesof the second bridge wiring layer 2004 are not electrically connected.

For example, the third wiring portion 203 located on the first side ofthe bridge sub-circuit board 200 is exposed and led out through the viahole 2011 in the second substrate 2001 and the opening 2015 in thesecond bridge insulation layer 2005, and for example, the third wiringportion 203 is surface-treated to form a plurality of patterned contactpads, thereby constituting the third bridge end 201 or the fourth bridgeend 202. For example, the opening 2015 in the second bridge insulationlayer 2005 is formed at the position indicated by the dotted frame shownin FIG. 8C or at other suitable positions, which is not limited in theembodiments of the present disclosure.

For example, as shown in FIG. 8D, in some embodiments, the bridgesub-circuit board 200 may further include a shield layer 2006 on asecond side of the second substrate 2001. The shield layer 2006 isprovided on the side of the second bridge insulation layer 2005 awayfrom the second substrate 2001, for example. For example, the shieldlayer 2006 is grounded, and can achieve the effect of electromagneticshielding. For example, the shield layer 2006 has a hollow structure2016 at a position corresponding to the opening 2015 of the secondbridge insulation layer 2005, thereby exposing the third bridge end 201or the fourth bridge end 202.

For example, in a case where the bridge sub-circuit board 200 is mountedon the main sub-circuit board 100, the second side is closer to the mainsub-circuit board 100 than the first side. Thus, the shield layer 2006is located between the wiring layers in the main sub-circuit board 100and the wiring layers in the bridge sub-circuit board 200, and theshield layer 2006 can prevent signal crosstalk generated between thewiring layers in the main sub-circuit board 100 and the wiring layers inthe bridge sub-circuit board 200.

For example, in some embodiments, the second bridge wiring layer 2004may be a (electrically) grounded layer, and may include a plurality ofground wiring lines. In this case, the third wiring portion 203 may beall disposed in the first bridge wiring layer 2002. Thus, there is alsoa (electrically) grounded layer between the wiring layers in the mainsub-circuit board 100 and the wiring layers in the bridge sub-circuitboard 200, the (electrically) grounded layer can further prevent signalcrosstalk generated between the wiring layers in the main sub-circuitboard 100 and the wiring layers in the bridge sub-circuit board 200.Alternatively, in some embodiments, a part of the third wiring portion203 may be disposed in the first bridge wiring layer 2002, and the otherpart of the third wiring portion 203 is disposed in the second bridgewiring layer 2004. In this case, the ground wiring lines in the secondbridge wiring layer 2004 and part wiring lines of the third wiringportion 203 may be alternately arranged. Thus, the second bridge wiringlayer 2004 can also play a role of preventing signal crosstalk.

In a case where the bridge sub-circuit board has a grounded layer and ashield layer 2006, the grounded layer 2004 and the shield layer 2006 canachieve a double shielding effect, thereby preventing the signalcrosstalk generated between the respective wiring lines on the mainsub-circuit board 100 and the respective wiring lines on the bridgesub-circuit board 200.

For example, in some embodiments, the bridge sub-circuit board 200 mayfurther include an insulation layer (not shown in the figure) located onthe outer side of the shield layer 2006 (i.e., a side away from thesecond substrate 2001) to provide protection to the shield layer 2006,and the insulation layer can be bonded to the shield layer 2006 by anadhesive layer, for example. The insulation layer may further include anopening corresponding to the opening 2015 and the hollow structure 2016to expose the bridge end. For example, the via hole 2011 in the secondsubstrate 2001 and the opening 2015 in the second bridge insulationlayer 2005 are misaligned, so that in the manufacturing process, theposition where the opening 1015 is located is relatively flat, therebyfacilitating the formation of the contact pads.

For example, in some embodiments, the third bridge end 201 and thefourth bridge end 202 of the bridge sub-circuit board 200 may be exposedon different sides of the bridge sub-circuit board 200, respectively, sothat the third bridge end 201 and the fourth bridge end 202 are disposedon different sides of the bridge sub-circuit board 200.

For example, FIG. 9A shows a schematic cross-sectional diagram ofanother bridge sub-circuit board provided by some embodiments of thepresent disclosure, for example, the cross-sectional diagram is obtainedby taking along a line D-D in FIG. 3A. In this embodiment, the bridgesub-circuit board has a single-layer wiring structure. For example, thethird bridge end 201 of the bridge sub-circuit board is exposed by thesecond substrate 2001, as shown in FIG. 8A; and the fourth bridge end202 is exposed by the opening 2013 in the first bridge insulation layer2003, as shown in FIG. 9A, so that the third bridge end 201 and thefourth bridge end 202 are disposed on different sides of the bridgesub-circuit board.

For example, FIG. 9B shows a schematic cross-sectional diagram ofanother bridge sub-circuit board provided by some embodiments of thepresent disclosure, for example, the cross-sectional diagram is obtainedby taking along the line D-D in FIG. 3A. In this embodiment, the bridgesub-circuit board has a double-layer wiring structure. For example, thethird bridge end 201 of the bridge sub-circuit board is exposed by thesecond bridge insulation layer 2005, as shown in FIG. 8C; and the fourthbridge end 202 is exposed by the opening 2013 in the first bridgeinsulation layer 2003, as shown in FIG. 9B, so that the third bridge end201 and the fourth bridge end 202 are disposed on different sides of thebridge sub-circuit board.

For example, in some embodiments, the bridge sub-circuit board may alsohave a multi-layer wiring structure, such as a three-layer wiringstructure, a four-layer wiring structure, or the like. In this case, thethird wiring portion on the bridge sub-circuit board can be arranged ina plurality of wiring layers. For example, the third wiring portion canbe alternately arranged in the plurality of wiring layers. Theembodiments of the present disclosure do not specifically limit thenumber of wiring layers of the bridge sub-circuit board and thearrangement of the wiring lines.

For example, in some embodiments, in a case where the first bridge end101 and the second bridge end 102 of the main sub-circuit board aredisposed on different sides of the main sub-circuit board, and the thirdbridge end 201 and the fourth bridge end 202 of the bridge sub-circuitboard are also disposed on different sides of the bridge sub-circuitboard, the third bridge end 201 and the fourth bridge end 202 of thebridge sub-circuit board may be respectively electrically connected tothe first bridge end 101 and the second bridge end 102 on differentsides of the main sub-circuit board, or, in a case where the firstbridge end 101 and the second bridge end 102 of the main sub-circuitboard are disposed on different sides of the main sub-circuit board, andthe third bridge end 201 and the fourth bridge end 202 of the bridgesub-circuit board are disposed on the same side of the bridgesub-circuit board, the third bridge end 201 and the fourth bridge end202 of the bridge sub-circuit board can be respectively electricallyconnected to the first bridge end 101 and the second bridge end 102 ondifferent sides of the main sub-circuit board by bending, so that thebridge sub-circuit board can be bridge-connected to the main sub-circuitboard in a form similar to a “hairpin”.

For example, the first substrate 1001 and the second substrate 2001 canbe made of flexible materials such as polyimide or polyester. Eachwiring layer can be made of metal materials such as copper, silver,aluminum, etc., or alloy materials thereof, and each insulation layercan be made of insulation materials such as polyimide or polyester, thegrounded layer 2004 can be made of a metal material (such as a copperlayer or a copper foil), and the shield layer 2006 includes aninsulation base and a conductive material filled in the insulation base,for example, the insulation base is made of epoxy resin, and the filledconductive material is copper powder, graphite powder, etc.;alternatively, in some embodiments, the shield layer 2006 may also bemade of a metal material, and the material of each functional layer isnot specifically limited in the present disclosure. The adhesive layermay adopt epoxy resin, polyethylene, or the like.

For example, the third bridge end 201 and the fourth bridge end 202 ofthe bridge sub-circuit board 200 are respectively connected to the firstbridge end 101 and the second bridge end 102 of the main sub-circuitboard 100 through an anisotropic conductive adhesive, a solder material,or a connector. For example, the connector includes a zero insertionforce (ZIF) connector or a board to board (BTB) connector, etc. Theembodiments of the present disclosure do not specifically limit theconnection method of the respective bridge ends.

For example, in one example, a board-to-board connector is used toconnect the main sub-circuit board 100 and the bridge sub-circuit board200. In this case, the connector includes a male connector and a femaleconnector that match with each other. For example, the first bridge end101 and the second bridge end 102 of the main sub-circuit board 100 areprovided with female connectors, and the third bridge end 201 and thefourth bridge end 202 of the bridge sub-circuit board 200 are providedwith male connectors, thereby connecting the bridge sub-circuit board200 to the main sub-circuit board 100 through matching the maleconnectors and the female connectors.

The flexible printed circuit provided by the embodiments of the presentdisclosure has a main sub-circuit board and a bridge sub-circuit board,by bridge-connecting the wiring lines located on two sides of the mainsub-circuit board through the bridge sub-circuit board, the wiring lineson the main sub-circuit board can be avoided from crossing, so thatsignal crosstalk can be prevented or reduced, or it is possible to avoidadding an additional functional layer to prevent signal crosstalk,thereby avoiding complexity of the circuit board structure. In someembodiments of the present disclosure, the main sub-circuit board andthe bridge sub-circuit board have a simple single-layer or double-layerstructure, so that the wiring layout is simpler, which can reduce thedifficulty of manufacturing the main sub-circuit board and the bridgesub-circuit board.

Some embodiments of the present disclosure provide an electronic devicemodule. FIG. 10A shows a schematic diagram of the electronic devicemodule. As shown in FIG. 10A, the electronic device module 1 includes anelectronic device substrate 11 and the flexible printed circuit 10described in any one of the above embodiments, the electronic devicesubstrate 11 includes a first functional circuit structure 20. The firstfunctional wiring line of the flexible printed circuit 10 (including thefirst wiring portion 103, the second wiring portion 104, and the thirdwiring portion 203) is electrically connected to the first functionalcircuit structure 20.

For example, in some embodiments, the flexible printed circuit 10further includes a second functional wiring line 106, the firstfunctional circuit structure 20 includes a first signal transmissionportion 21 and a second signal transmission portion 22, the firstfunctional wiring line is electrically connected to the first signaltransmission portion 21, and the second functional wiring line 106 iselectrically connected to the second signal transmission portion 22.

For example, in some embodiments, the electronic device substrate 11further includes a second functional circuit structure 23, and theflexible printed circuit further includes a third functional wiring line107, and the third functional wiring line 107 is electrically connectedto the second functional circuit structure 23.

For example, in some embodiments, the electronic device substrate 11 isa substrate having a display function and a touch function. In thiscase, the first functional circuit structure 20 is a touch circuitstructure, and the second functional circuit structure 23 is a displaycircuit structure. In other embodiments, the electronic device substrate11 is a substrate with a display function and a fingerprint recognitionfunction, in this case, the first functional circuit structure 20 is afingerprint recognition circuit structure, for example, the fingerprintrecognition circuit structure is a capacitive fingerprint recognitioncircuit, the capacitive fingerprint recognition circuit includesdetection drive electrodes and detection sensing electrodes arrangedcrosswise, and the second functional circuit structure 23 is a displaycircuit structure. The following embodiment is described by taking acase where the first functional circuit structure 20 is a touch circuitstructure as an example.

For example, the manner in which the touch circuit structure is providedon the electronic device substrate 11 may be an in-cell type or anon-cell type. The form of the touch circuit structure may be acapacitive type, such as a mutual-capacitive touch circuit structure.For example, the mutual-capacitive touch circuit structure includes aplurality of first electrodes extending in a first direction and aplurality of second electrodes extending in a second direction (crossingthe first direction), detection capacitors will be formed at positionswhere the two groups of electrodes cross, that is, the two groups ofelectrodes constitute the two electrodes of the capacitors. In a casewhere the finger touches the touch circuit structure, the finger affectsthe coupling state between the two electrodes near the touch point,thereby changing the capacitance of the detection capacitor formed bythe two electrodes. According to the capacitance change data of thetouch circuit structure and the coordinates of the respectivecapacitors, the coordinates of each touch point can be obtained. In acase of detecting the capacitance value of the capacitor, the horizontalelectrodes serve as the touch driving circuit and sequentially send outexcitation signals, and the vertical electrodes serve as the touchsensing circuit and receive signals simultaneously or sequentially, sothat the capacitance values of all intersection points of the horizontalelectrodes and the vertical electrodes, that is, the capacitance valuesof the two-dimensional plane of the entire touch structure, can beobtained. Therefore, even if there are a plurality of touch points onthe touch circuit structure, the true coordinates of each touch pointcan be determined.

For example, in the above case, the first signal transmission portion 21may include a touch driving wiring line electrically connected to atouch driving (Tx) circuit of the touch circuit structure, and thesecond signal transmission portion 22 may include a touch sensing wiringline electrically connected to a touch sensing (Rx) circuit of the touchcircuit structure. In this case, the first control circuit 1051 is atouch driving IC, which can provide an excitation signal for the touchdriving circuit through the touch driving wiring line, and can receivethe sensing signal of the touch sensing circuit through the touchsensing wiring line, and can determine the touch position and respondsbased on the above signals. For example, in the above example, the touchdriving circuit is bridge-connected, and the touch sensing circuit isdirectly electrically connected to the first control circuit combinationstructure 105, so that the distance between the touch sensing circuitand the first control circuit combination structure 105 is closer, i.e.,the touch sensing circuit is closer to the first control circuit 1051mounted on the first control circuit combination structure 105, namely,the distance between the touch sensing circuit and the touch driving ICis closer. Therefore, the transmission path for transmitting the sensingsignal received by the touch sensing circuit to the touch driving IC isshorter, so that the sensing signal is less likely to be interfered byanother signal, so that the touch operation can be more accurate. Forexample, as shown in FIG. 10A, the touch driving wiring line and thetouch sensing wiring line extend to the same side of the electronicdevice substrate 11 (the lower side in the figure), and are respectivelyelectrically connected to the contact pad 211 and the contact pad 221formed on the side.

For example, in other embodiments of the present disclosure, the firstsignal transmission portion 21 may include a touch sensing wiring lineelectrically connected to a touch sensing (Rx) circuit of the touchcircuit structure, and the second signal transmission portion 22includes a touch driving wiring line electrically connected to a touchdriving (Tx) circuit of the touch circuit structure, in this case, thetouch sensing circuit is bridge-connected, and the touch driving circuitis directly electrically connected to the first control circuitcombination structure 105, so that the distance between the touchdriving circuit and the first control circuit combination structure 105is closer, that is, the touch driving circuit is closer to the firstcontrol circuit 1051 mounted on the first control circuit combinationstructure 105, that is, the distance between the touch driving circuitand the touch driving IC is closer. Therefore, in the embodiment, thetouch driving signal in the touch driving circuit is less likely to beinterfered by another signal.

For example, the flexible printed circuit 10 has a wiring connection end110 on one side (for example, the upper side in the figure) of theflexible printed circuit 10, the wiring connection end 110 has aplurality of contact pads, and the other ends of the plurality of wiringlines included in the second wiring portion 104 are electricallyconnected to part of the contact pads in the wiring connection end 110in one-to-one correspondence, and the other ends of the plurality ofwiring lines included in the second functional wiring line 106 areelectrically connected to another part of the contact pads in the wiringconnection end 110 in one-to-one correspondence, in addition, the otherends of the plurality of wiring lines included in the third functionalwiring line 107 are electrically connected to further another part ofthe contact pads in the wiring connection end 110 in one-to-onecorrespondence. For example, contact pads electrically connected to thesecond wiring portion 104, contact pads electrically connected to thethird functional wiring line 107, and contact pads electricallyconnected to the second functional wiring line 106 are arranged atintervals or continuously on the wiring connection end 110, which is notspecifically limited in the embodiments of the present disclosure. Forexample, in a case where the number of wiring lines in the second wiringportion 104, the third functional wiring line 107, and the secondfunctional wiring line 106 is large, the contact pads connected to thesewiring lines may be continuously arranged on the wiring connection end110; in a case where the number of wiring lines in the second wiringportion 104, the third functional wiring line 107, and the secondfunctional wiring line 106 is small, the contact pads connected to thesewiring lines may be arranged at intervals on the wiring connection end110, and in this case, for example, a plurality of sets of contact padsarranged at intervals shown in FIG. 10A may be formed.

For example, the wiring connection end 110 is provided in a wiringconnection region 110A of the main sub-circuit board (that is, theoblique line region below the wiring connection end 110 in the figure),for example, the wiring connection region 110A only has a wiring layerand a part of the insulation layer, and does not have the shield layerand other structures, therefore, the wiring connection region 110A hashigh transparency. In a case where the flexible printed circuit 10 isconnected to the electronic device substrate 11, clear alignment can beachieved, so as to facilitate accurate electrical connection between theflexible printed circuit 10 and the electronic device substrate 11.

For example, in a case where the flexible printed circuit 10 isconnected to the electronic device substrate 11, the contact pads of thewiring connection end 110 on the side of the flexible printed circuit 10and the contact pads on the side of the electronic device substrate 11may be directly pressure-connected together. For example, in someembodiments, the contact pads of the wiring connection end 110 on theside of the flexible printed circuit 10 and the contact pads on the sideof the electronic device substrate 11 are electrically connected to eachother by, for example, ACF, thereby electrically connecting the firstfunctional wiring line on the flexible printed circuit 10 with the touchdriving wiring line connected to the first signal transmission portion21 through the contact pads 211, and electrically connecting the secondfunctional wiring line on the flexible printed circuit 10 with the touchsensing wiring line connected to the second signal transmission portion22 through the contact pads 221, as a result, the first functionalwiring line and the second functional wiring line of the flexibleprinted circuit 10 are electrically connected to the touch circuitstructure of the electronic device substrate 11.

For example, the second functional circuit structure 23, that is, thedisplay circuit structure, includes a plurality of data lines (and alsoincludes gate lines, etc.), the plurality of data lines are electricallyconnected to pixel units, respectively, and the plurality of data linesextend to one side (the lower side in the figure) of the electronicdevice substrate 11, and are electrically connected to the contact pads231 formed on the side. In a case of an organic light-emitting diode(OLED) display substrate, the pixel unit includes a display drivingcircuit. For example, the display driving circuit includes a pluralityof transistors, capacitors, light-emitting devices, and the like. Forexample, the display driving circuit is formed in various forms such as2T1C, 3T1C, or 7T1C. For example, in a case where the flexible printedcircuit 10 is connected to the electronic device substrate 11, theplurality of contact pads provided on the wiring connection end 110 ofthe flexible printed circuit 10 also electrically connect the thirdfunctional wiring line on the flexible printed circuit to the data lines23 in the second functional circuit structure through the contact pads231, thereby electrically connecting the third functional wiring line ofthe flexible printed circuit 10 to the display circuit structure of theelectronic device substrate 11.

For example, in some embodiments, as shown in FIG. 10B, the mainsub-circuit board 100 may further have a second control circuitcombination structure 108 and a second control circuit 1081 provided onthe second control circuit combination structure 108. In this case, thesecond control circuit 1081 is a display driving IC, and the displaydriving IC can provide a data signal for the display driving circuit, sothat a light-emitting state of the light-emitting device can becontrolled by the data signal provided by the display driving IC toachieve different display effects.

In a case of a liquid crystal display (LCD) substrate, the pixel unitincludes a switching element and a first electrode (pixel electrode) anda second electrode (common electrode) for controlling the deflection ofthe liquid crystal, and the switching element is electrically connectedto the first electrode. The second functional circuit structure 23, thatis, the display circuit structure, includes a plurality of data linesrespectively connected to the pixel units. In this case, the secondcontrol circuit is a display driving IC, and the display driving IC canprovide different data voltage signals to the pixel unit through thedata line, thereby controlling the twisting state of the liquid crystalto achieve different display effects.

For example, the flexible printed circuit is connected to the electronicdevice substrate 11 by binding. During the binding process, the flexibleprinted circuit may be bent to the back of the electronic devicesubstrate 11 and fixed after being bound to the electronic devicesubstrate 11, that is, the flexible printed circuit is mounted on anon-display side of the electronic device substrate 11 in order tofacilitate the large-screen design of the display screen.

In the flexible printed circuit of the electronic device substrate insome embodiments of the present disclosure described above, the wiringportions, which are respectively electrically connected to the touchdriving circuit, on the main sub-circuit board are bridge-connectedthrough the bridge sub-circuit board, so that the touch driving circuitand the display driving circuit do not intersect on the main sub-circuitboard, and the touch driving circuit and the display driving circuit arealso shielded from each other at the intersection position of the mainsub-circuit board and the bridge sub-circuit board, and therefore thesignal crosstalk between the wiring lines in the main sub-circuit boardand the wiring lines in the bridge sub-circuit board can be avoided, atthe same time, the structure of the main sub-circuit board and thestructure of the bridge sub-circuit board are simple, and the wiringlayout is simple, which is beneficial to simplify the manufacturingprocess of the flexible printed circuit.

At least one embodiment of the present disclosure provides an electronicdevice. FIG. 11 shows a schematic diagram of the electronic device. Asshown in FIG. 11 , the electronic device 2 includes any one of the aboveelectronic device modules. The electronic device module includes anelectronic device substrate 11 and a flexible printed circuit 10. Forexample, an upper side of the electronic device substrate 11 shown inFIG. 11 is a display side, and a lower side is a non-display side; inthis case, the flexible printed circuit 10 is bent and placed on thenon-display side of the electronic device substrate 11 after being boundto the electronic device substrate 11, so as to achieve the large-screendesign of the display screen.

The electronic device 2 may be, for example, any product or componentwith a display function such as a mobile phone, a tablet computer, a TV,a display, a notebook computer, a digital photo frame, a navigator, etc.The embodiments of the present disclosure are not limited in thisaspect.

Some embodiments of the present disclosure provide a manufacturingmethod for a flexible printed circuit. As shown in FIG. 12 , themanufacturing method includes steps S101-S103.

Step S101: providing a main sub-circuit board.

Referring to FIG. 2 , the main sub-circuit board 100 includes a firstbridge end 101, a second bridge end 102, a first wiring portion 103, anda second wiring portion 104. The first wiring portion 103 and the secondwiring portion 104 are spaced apart from each other and are electricallyconnected to the first bridge end 101 and the second bridge end 102,respectively.

For example, referring to FIG. 6A, the main sub-circuit board 100 isformed by sequentially forming a first wiring layer 1002 and a firstinsulation layer 1003 on the first substrate 1001. For example, thefirst substrate 1001 is made of materials such as polyimide orpolyester, the first wiring layer 1002 is made of metal materials suchas copper, silver, aluminum, etc., or alloy materials thereof, and thefirst insulation layer 1003 is also made of materials such as polyimideor polyester. For example, firstly, a copper metal layer is formed onthe first substrate 1001 by sputtering or the like, secondly, the coppermetal layer is patterned to form the first wiring layer 1002, and then afirst insulation layer 1003 is formed on the first wiring layer 1002 bycoating or the like, and an opening is formed in the first insulationlayer 1003 to form a structure such as a bridge end.

Step S102: providing a bridge sub-circuit board.

Referring to FIG. 3 , the bridge sub-circuit board 200 includes a thirdbridge end 201, a fourth bridge end 202, and a third wiring portion 203,and the third bridge end 201 and the fourth bridge end 202 areelectrically connected by the third wiring portion 203.

For example, referring to FIG. 8A, the bridge sub-circuit board 200 isformed by sequentially forming a first bridge wiring layer 2002 and afirst bridge insulation layer 2003 on a first side of the secondsubstrate 2001. For example, the first substrate 2001 is made ofmaterials such as polyimide or polyester, the first bridge wiring layer2002 is made of metal materials, such as copper, silver, aluminum, oralloy materials thereof, and the first bridge insulation layer 2003 isalso made of materials such as polyimide or polyester. For example,firstly, a copper metal layer is formed on the second substrate 2001 bysputtering or the like, then the copper metal layer is patterned to formthe first bridge wiring layer 2002, and then a first bridge insulationlayer 2003 is formed on the first bridge wiring layer 2002 by coating orthe like.

For example, referring to FIG. 8C, in some embodiments, forming thebridge sub-circuit board 200 further includes sequentially forming asecond bridge wiring layer 2004 and a second bridge insulation layer ona second side of the second substrate 2001 opposite to the first side2005. For example, the second bridge wiring layer 2004 may be a(electrically) grounded layer, and is made of copper or other materials,and the second bridge insulation layer 2005 is made of materials such aspolyimide or polyester. For example, openings (or via holes) are formedin the second substrate 2001 and the second bridge insulation layer 2005by patterning, etc., the third wiring portion 203 formed on the firstside of the bridge sub-circuit board 200 is exposed and led out throughthe via hole 2011 in the second substrate 2001 and the opening 2015 inthe second bridge insulation layer 2005, and for example, the thirdwiring portion 203 is surface-treated to form a plurality of contactpads, thereby constituting the bridge end.

For example, referring to FIG. 8C, in some embodiments, forming thebridge sub-circuit board 200 further includes forming a shield layer2006 on the second side of the second substrate 2001. For example, theshield layer 2006 is suspended, or is configured to be electricallyconnected to a ground line.

For example, in some embodiments, as shown in FIG. 8D, in a case wherethe second bridge wiring layer 2004 is a grounded layer, an opening 2025is further formed in the second bridge insulation layer 2005, and theshield layer 2006 is connected to the ground line in the second bridgewiring layer 2004 through the opening 2025.

For example, in a case where the second bridge wiring layer 2004 is agrounded layer, the grounded layer 2004 and the shield layer 2006 canachieve a double shielding effect, thereby preventing signal crosstalkgenerated between each wiring line on the main sub-circuit board 100 andeach wiring line on the bridge sub-circuit board 200. For example, theshield layer 2006 is formed with a hollow structure 2016 at a positioncorresponding to the opening 2015 of the second bridge insulation layer2005, thereby exposing the bridge end.

For example, the shield layer 2006 includes an insulation base and aconductive material filled in the insulation base, for example, theinsulation base is made of epoxy resin, and the filled conductivematerial is copper powder, graphite powder, etc., alternatively, in someembodiments, the shield layer 2006 may also be made of a metal material,and the embodiments of the present disclosure do not specifically limitthis. For example, the shield layer may be directly attached to thesecond side of the bridge sub-circuit board 200 after being formed.

Step S103: mounting the bridge sub-circuit board on the main sub-circuitboard.

Referring to FIG. 1A, the third bridge end 201 and the fourth bridge end202 of the bridge sub-circuit board 200 are electrically connected tothe first bridge end 101 and the second bridge end 102 of the mainsub-circuit board 100, respectively, so that the bridge sub-circuitboard 200 is mounted on the main sub-circuit board 100, and the firstwiring portion 103, the third wiring portion 203, and the second wiringportion 104 are electrically connected in sequence to obtain a firstfunctional wiring line. During the mounting process, the second side ofthe bridge sub-circuit board 200 is closer to the main sub-circuit board100 than the first side of the bridge sub-circuit board 200, so that thewiring lines on the main sub-circuit board 100 and the wiring lines onthe bridge sub-circuit board 200 can be shielded by the grounded layer2004 and the shield layer 2006 to prevent signal crosstalk.

For example, the third bridge end 201 and the fourth bridge end 202 ofthe bridge sub-circuit board 200 can be respectively connected to thefirst bridge end 101 and the second bridge end 102 of the mainsub-circuit board 100 by a hot pressing method, a welding method, orthrough a connector. For example, in the hot pressing method, ananisotropic conductive adhesive is formed between the two bridge ends,and then the bridge ends are hot pressed, so as to connect the twobridge ends together through the anisotropic conductive adhesive. Forexample, the connector includes a zero insertion force (ZIF) connectoror a board to board (BTB) connector, etc. The embodiments of the presentdisclosure do not specifically limit the connection method.

For example, in one example, a board-to-board connector is used toconnect the main sub-circuit board 100 and the bridge sub-circuit board200. In this case, the connector includes a male connector and a femaleconnector that match with each other. For example, the first bridge end101 and the second bridge end 102 of the main sub-circuit board 100 areprovided with female connectors, and the third bridge end 201 and thefourth bridge end 202 of the bridge sub-circuit board 200 are providedwith male connectors, thereby connecting the bridge sub-circuit board200 to the main sub-circuit board 100 through matching the maleconnectors and the female connectors.

The manufacturing method for the flexible printed circuit of theembodiments of the present disclosure provides a main sub-circuit boardand a bridge sub-circuit board, by bridge-connecting the wiring lineslocated on two sides of the main sub-circuit board through the bridgesub-circuit board, the method can avoid the wiring lines on the mainsub-circuit board from crossing, prevent or reduce signal crosstalk, orit is possible to avoid adding an additional functional layer to preventsignal crosstalk, thereby avoiding complexity of the circuit boardstructure. In addition, the main sub-circuit board and the bridgesub-circuit board provided by the manufacturing method have a simplesingle-layer or double-layer structure, so that the wiring layout issimpler, which can reduce the difficulty of manufacturing the mainsub-circuit board and the bridge sub-circuit board.

The following statements should be noted:

(1) The accompanying drawings involve only the structure(s) inconnection with the embodiment(s) of the present disclosure, and otherstructure(s) can be referred to common design(s).

(2) For the purpose of clarity only, in accompanying drawings forillustrating the embodiment(s) of the present disclosure, the thicknessand size of a layer or a structure may be enlarged or narrowed, that is,the drawings are not drawn in a real scale. However, it shouldunderstood that, in the case in which a component such as a layer, film,region, substrate or the like is referred to be “on” or “under” anothercomponent, the component may be directly on or under the anothercomponent or there may be an intermediate component.

(3) In case of no conflict, the embodiments of the present disclosureand the features in the embodiments can be combined with each other toobtain new embodiments.

What have been described above are only specific implementations of thepresent disclosure, the protection scope of the present disclosure isnot limited thereto. Any modifications or substitutions easily occur tothose skilled in the art within the technical scope of the presentdisclosure should be within the protection scope of the presentdisclosure. Therefore, the protection scope of the present disclosureshould be based on the protection scope of the claims.

1. A flexible printed circuit, comprising: a main sub-circuit board, comprising a first substrate, and a first bridge end, a second bridge end, a first wiring portion, and a second wiring portion on the first substrate, wherein the first wiring portion and the second wiring portion are spaced apart from each other and are electrically connected to the first bridge end and the second bridge end, respectively; the first bridge end comprises a plurality of first contact pads, and the plurality of first contact pads are correspondingly connected with a plurality of wiring lines of the first wiring portion; the second bridge end comprises a plurality of second contact pads, and the plurality of second contact pads are correspondingly connected with a plurality of wiring lines of the second wiring portion; and a bridge sub-circuit board, comprising a second substrate, and a third bridge end, a fourth bridge end, and a third wiring portion for a first functional wiring line on the second substrate, wherein the third bridge end and the fourth bridge end are electrically connected by the third wiring portion, wherein the bridge sub-circuit board is configured to be mounted on the main sub-circuit board by electrically connecting the third bridge end and the fourth bridge end to the first bridge end and the second bridge end, respectively.
 2. The flexible printed circuit according to claim 1, wherein the bridge sub-circuit board is mounted on the main sub-circuit board, and the first wiring portion, the third wiring portion, and the second wiring portion are electrically connected in sequence to obtain the first functional wiring line.
 3. The flexible printed circuit according to claim 1, further comprising a first control circuit combination structure, wherein the first control circuit combination structure is on the main sub-circuit board and is electrically connected to the first wiring portion, or the first control circuit combination structure is on the bridge sub-circuit board and is electrically connected to the third wiring portion; the first control circuit combination structure is configured to provide a first electrical signal to the first functional wiring line or receive a first electrical signal from the first functional wiring line.
 4. The flexible printed circuit according to claim 3, wherein the main sub-circuit board further comprises a second functional wiring line, the second functional wiring line is electrically connected to the first control circuit combination structure on the main sub-circuit board, and the first control circuit combination structure is further configured to provide a second electrical signal to the second functional wiring line or receive a second electrical signal from the second functional wiring line.
 5. The flexible printed circuit according to claim 4, wherein the main sub-circuit board further comprises a third functional wiring line, and the third functional wiring line is between the first wiring portion and the second wiring portion, and crosses the bridge sub-circuit board mounted on the main sub-circuit board.
 6. The flexible printed circuit according to claim 5, wherein the first wiring portion, the second wiring portion, and the third functional wiring line are routed in a same direction.
 7. The flexible printed circuit according to claim 1, wherein the main sub-circuit board comprises a first main wiring layer on a first side of the first substrate and a first main insulation layer stacked on a side of the first main wiring layer away from the first substrate, the first main wiring layer comprises the first wiring portion, the second wiring portion, the first bridge end, and the second bridge end, and the first bridge end and the second bridge end are exposed by the first main insulation layer.
 8. The flexible printed circuit according to claim 7, wherein the main sub-circuit board further comprises a second main wiring layer, on a second side of the first substrate opposite to the first side, and a second main insulation layer stacked on a side of the second main wiring layer away from the first substrate, and the second main wiring layer comprises the first wiring portion and the second wiring portion.
 9. The flexible printed circuit according to claim 1, wherein the main sub-circuit board comprises a first main wiring layer on a first side of the first substrate and a first main insulation layer stacked on a side of the first main wiring layer away from the first substrate, the main sub-circuit board further comprises a second main wiring layer, on a second side of the first substrate opposite to the first side, and a second main insulation layer stacked on a side of the second main wiring layer away from the first substrate, the first main wiring layer comprises the first wiring portion, the second wiring portion, and the first bridge end, and the first bridge end is exposed by the first main insulation layer; the second main wiring layer comprises the first wiring portion, the second wiring portion, and the second bridge end, and the second bridge end is exposed by the second main insulation layer.
 10. The flexible printed circuit according to claim 1, wherein the bridge sub-circuit board comprises a first bridge wiring layer on a first side of the second substrate and a first bridge insulation layer stacked on a side of the first bridge wiring layer away from the second substrate, and the first bridge wiring layer comprises the third wiring portion.
 11. The flexible printed circuit according to claim 10, wherein the bridge sub-circuit board further comprises a grounded layer on a second side of the second substrate opposite to the first side, and in a case where the bridge sub-circuit board is mounted on the main sub-circuit board, the second side is closer to the main sub-circuit board than the first side.
 12. The flexible printed circuit according to claim 11, wherein the bridge sub-circuit board further comprises a shield layer on the second side of the second substrate, and the shield layer is stacked on a side of the grounded layer away from the second substrate.
 13. The flexible printed circuit according to claim 10, wherein the bridge sub-circuit board further comprises a second bridge wiring layer on a second side of the second substrate opposite to the first side, and a second bridge insulation layer stacked on a side of the second bridge wiring layer away from the second substrate, the second bridge wiring layer comprises the third wiring portion, the third bridge end, and the fourth bridge end, the third bridge end and the fourth bridge end are exposed by the second bridge insulation layer; and in a case where the bridge sub-circuit board is mounted on the main sub-circuit board, the second side is closer to the main sub-circuit board than the first side.
 14. The flexible printed circuit according to claim 10, wherein the bridge sub-circuit board further comprises a second bridge wiring layer on a second side of the second substrate opposite to the first side, and a second bridge insulation layer stacked on a side of the second bridge wiring layer away from the second substrate, the first bridge wiring layer further comprises the third bridge end, and the third bridge end is exposed by the first bridge insulation layer; and the second bridge wiring layer comprises the third wiring portion and the fourth bridge end, and the fourth bridge end is exposed by the second bridge insulation layer.
 15. The flexible printed circuit according to claim 13, wherein the bridge sub-circuit board further comprises a shield layer on the second side of the second substrate and stacked on a side of the second bridge insulation layer away from the second substrate.
 16. The flexible printed circuit according to claim 1, wherein the third bridge end and the fourth bridge end of the bridging sub-circuit board are respectively connected to the first bridge end and the second bridge end of the main sub-circuit board through an anisotropic conductive adhesive, a solder material, or a connector.
 17. The flexible printed circuit according to claim 1, wherein the main sub-circuit board comprises a plurality of first bridge ends and a plurality of second bridge ends; the flexible printed circuit comprises a plurality of bridge sub-circuit boards, and the plurality of bridge sub-circuit boards are mounted on the main sub-circuit board by electrically connecting a plurality of third bridge ends and a plurality of fourth bridge ends to the plurality of first bridge ends and the plurality of second bridge ends, respectively.
 18. An electronic device module, comprising: an electronic device substrate, and the flexible printed circuit according to claim 1, wherein the electronic device substrate comprises a first functional circuit structure, and the first functional wiring line of the flexible printed circuit is electrically connected to the first functional circuit structure.
 19. The flexible printed circuit according to claim 1, wherein the first substrate and the second substrate are not in direct contact. 